1. Field of the Invention
The present invention relates to a photosensitive-recording medium cartridge, and a shutter lock canceling mechanism, and more particularly to a photosensitive-recording medium cartridge, and shutter lock canceling mechanism in which a shutter of a photosensitive recording medium is locked, and, when a photosensitive recording medium is loaded into a recording and reproducing apparatus, cancellation of engagement of a locking mechanism of the shutter can be surely allowed.
2. Background Art
A hologram recording medium on which data are recorded by hologram has been developed. The hologram recording medium is a photosensitive recording medium in which a hologram recording layer made of a photosensitive material is laminated on a disk-like support member, and data are recorded in multilayers in the form of interference fringes of a laser beam, so that it is possible to obtain a data recording capacity which is larger than that of a DVD that is widely used in a conventional art. In the hologram recording medium, when the hologram recording layer is exposed to light or a dust adheres to the layer, the performance is adversely affected. Therefore, the hologram recording medium is handled while being housed in a cartridge having light shielding and dust proof functions.
As a cartridge for housing a hologram recording medium, a cartridge is known that includes: a cartridge body in which an opening for exposing the hologram recording medium to the outside; a shutter which opens and closes the opening; and a light-shielding plate disposed outside the shutter (for example, see JP-A-2001-216754 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”)). When the cartridge is inserted into a recording and reproducing apparatus which writes data on or reads data from the hologram recording layer, the shutter is opened by the function of a shutter opening member disposed in the recording and reproducing apparatus.
When the shutter is accidentally opened, there is the possibility that the hologram recording medium is exposed to light and cannot be used. Therefore, also a cartridge is known in which a locking mechanism including an elastic piece extending from a shutter and having an engaging claw at the tip end is disposed, and the engaging claw is engaged with a first or second engaging recess formed in an outer case, thereby holding the shutter at a closing or opening position (for example, see JP-A-8-055456).
The cartridge disclosed in Patent Reference 1 includes the shutter for light shielding and dust proof, but fails to include a shutter locking mechanism which blocks the opening of the shutter. In the cartridge, therefore, there is the possibility that the shutter is accidentally opened.
The disk cartridge disclosed in Patent Reference 2 includes the shutter locking mechanism configured by the first or second engaging recess formed in the outer case, and the engaging claw. The shutter is held at the closing or opening position. However, the engagement between the first or second engaging recess and the engaging claw is easily canceled simply by pressing the elastic piece having the engaging claw. Therefore, it is requested to develop a highly-reliable shutter locking mechanism in which a locking state can be maintained more surely.
As such a highly-reliable shutter locking mechanism, it may be contemplated to employ a shutter locking mechanism in which the locking mechanism is set to a cancellation-enabled state by a first operation, and a locking state is canceled by a second operation, so that the lock cancellation requires a two-step operation. From the viewpoint of improving the operability, it is preferable to automatically perform the first operation of setting the locking mechanism to the cancellation-enabled state, when a cartridge is loaded into a recording and reproducing apparatus. However, the relative position between the cartridge loaded into the recording and reproducing apparatus and the recording and reproducing apparatus is hardly maintained constant under the influences due to the gap between the cartridge and a cartridge housing portion of the recording and reproducing apparatus, component tolerances, and the like. In the case where a lock canceling mechanism disposed on the side of the cartridge is caused to operate by a shutter opening member disposed on the side of the recording and reproducing apparatus, therefore, there is the possibility that the lock cancellation is incompletely performed and the subsequent shutter opening cannot be conducted.
The invention has been conducted in view of the above-discussed circumstances. It is an object of the invention to provide a photosensitive-recording medium cartridge and shutter lock canceling mechanism which include a shutter locking mechanism that, when locking of a shutter is to be cancelled, requires a two-step operation of a first operation of setting the locking mechanism to a cancellation-enabled state, and a second operation of then canceling the locking, whereby cancellation of engagement of the locking mechanism by the first operation can be surely allowed.